Roger Wilco, space janitor, is aboard the research ship Arcada. His home system, Earnon is facing crisis as their sun is reaching the end of its natural life. Arcada has been sent to develop a device called the Star Generator, which is capable of transforming any planet from rock into the blazing nuclear furnace otherwise known as a star.

Roger is awoken from one of his famous broom closet naps by the sound of an alarm, and discovers most of the crew are dead. Further, he stumbles through a blasted door into the Star Generator lab and notices it's gone. Several vicious looking soldiers in red uniforms are searching the ship for survivors. Roger, meanwhile, comes across a mortally wounded scientist who tells him to retrieve an information cartridge from the archives and flee the Arcada.

Cartridge in hand, Roger makes his way down to the vehicle bay, puts on an EVA suit and escapes in a pod. Unfortunately, the pod's autopilot locks onto a desolate desert planet called Kerona and makes a very hard landing. As Roger is wandering hopelessly around a small canyon, a Sarien spiderdroid falls from the sky and begins looking for him - those alien soldiers saw his escape.

By pure dumb luck Roger stumbles into a cave and negotiates numerous obstacles (including a tentacle monster, acid pools and laser beams) to be confronted with a huge alien head. The head promises to assist him if Roger will but dispose of a creature on the surface known as Orat. Cleverly luring the spiderdroid so it attacks Orat instead, Roger secures the assistance of the aliens, who provide him with a sandskimmer. He also is finally able to read the information cartridge and discovers it contains the autodestruct code for the Star Generator, together with backup schematics.

Using the skimmer, Roger successfully reaches the main settlement on Kerona, Ulence Flats. Selling the skimmer for some money and a jetpack, he wins a small fortune on the local bar's slot machine and uses the proceeds to buy a used spaceship and pilot droid, before heading off in pursuit of the Sariens, the alien soldiers.

Using the jetpack to infiltrate the Sarien battlecruiser Deltaur, Roger dons a Sarien uniform and successfully locates the Star Generator. Disabling the guard, he punches in the autodestruct code. Unfortunately, the klutz that he is, he loses his helmet and has to blast his way to an escape pod, escaping explosive death yet again.

What made Space Quest great was the really quite excellent sense of humour that pervaded throughout. Sierra's games of the time were mostly really sickening King's Quest crap, and the very twisted, adult humour in Space Quest made for a pleasant change.

The game was also laden with science fiction and pop culturereferences, such as:

The only real problem was that it was incredibly easy to die, in fact, just getting off Arcada before the Sariens blew it up was no small feat.

UPDATE: Several noders have since reminded me it was also possible to kill Orat by throwing the can of dehydrated water (from the pod's survial kit) at him. Heck, it's also worth letting him catch you once to see what he does. I did know this, guys, it's just that method loses you the water (which you might need returning to the cave) and also gets you less points. Likewise, you can kill the spiderdroid by pushing the rock next to the natural bridge onto it. But this isn't a walkthrough ^_^